pages (blog/view): move URL friendly code to backend tools: - the code to render an URL friendly is now in `sat.tools.common.regex` - user friendly extra text is now only displayed when no `-` is found in ID. This is a temporary transition behaviour because new blog items IDs are now user friendly by default, and thus extra text is not wanted anymore. For older IDs it is still needed though, and the presence of `-` is used to guess when an ID is user friendly or not.